[1792] 2008-08-07 Christian Franke <[email protected]>

Revision: 1792
          http://svn.sv.gnu.org/viewvc/?view=rev&root=grub&revision=1792
Author:   chrfranke
Date:     2008-08-07 19:43:36 +0000 (Thu, 07 Aug 2008)

Log Message:
-----------
2008-08-07  Christian Franke  <[email protected]>

	* kern/i386/pit.c (TIMER2_SPEAKER): New define.
	(TIMER2_GATE): Likewise.
	(grub_pit_wait): Add enable/disable of the timer2 gate
	bit of port 0x61.  This fixes a possible infinite loop.

Modified Paths:
--------------
    trunk/grub2/ChangeLog
    trunk/grub2/kern/i386/pit.c

Modified: trunk/grub2/ChangeLog
===================================================================
--- trunk/grub2/ChangeLog	2008-08-07 19:21:25 UTC (rev 1791)
+++ trunk/grub2/ChangeLog	2008-08-07 19:43:36 UTC (rev 1792)
@@ -1,3 +1,10 @@
+2008-08-07  Christian Franke  <[email protected]>
+
+	* kern/i386/pit.c (TIMER2_SPEAKER): New define.
+	(TIMER2_GATE): Likewise.
+	(grub_pit_wait): Add enable/disable of the timer2 gate
+	bit of port 0x61.  This fixes a possible infinite loop.
+
 2008-08-07  Bean  <[email protected]>
 
 	* conf/x86_64-efi.rmk (kernel_mod_SOURCES): Add kern/time.c,

Modified: trunk/grub2/kern/i386/pit.c
===================================================================
--- trunk/grub2/kern/i386/pit.c	2008-08-07 19:21:25 UTC (rev 1791)
+++ trunk/grub2/kern/i386/pit.c	2008-08-07 19:43:36 UTC (rev 1792)
@@ -28,13 +28,29 @@
 #define TIMER_ENABLE_LSB	0x20
 #define TIMER_ENABLE_MSB	0x10
 #define TIMER2_LATCH		0x20
+#define TIMER2_SPEAKER		0x02
+#define TIMER2_GATE		0x01
 
 void
 grub_pit_wait (grub_uint16_t tics)
 {
+  /* Disable timer2 gate and speaker.  */
+  grub_outb (grub_inb (TIMER2_REG_LATCH) & ~ (TIMER2_SPEAKER | TIMER2_GATE),
+             TIMER2_REG_LATCH);
+
+  /* Set tics.  */
   grub_outb (TIMER2_SELECT | TIMER_ENABLE_LSB | TIMER_ENABLE_MSB, TIMER_REG_COMMAND);
   grub_outb (tics & 0xff, TIMER2_REG_CONTROL);
   grub_outb (tics >> 8, TIMER2_REG_CONTROL);
 
+  /* Enable timer2 gate, keep speaker disabled.  */
+  grub_outb ((grub_inb (TIMER2_REG_LATCH) & ~ TIMER2_SPEAKER) | TIMER2_GATE,
+             TIMER2_REG_LATCH);
+
+  /* Wait.  */
   while ((grub_inb (TIMER2_REG_LATCH) & TIMER2_LATCH) == 0x00);
+
+  /* Disable timer2 gate and speaker.  */
+  grub_outb (grub_inb (TIMER2_REG_LATCH) & ~ (TIMER2_SPEAKER | TIMER2_GATE),
+             TIMER2_REG_LATCH);
 }